Bitcoin developer Casey Rodarmor’s launch of Ordinals continues to emanate shockwaves of unintended outcomes. His innovative, controversial use of Bitcoin’s Taproot and Segwit upgrades has not only created a new type of Bitcoin NFT but also a new class of blockchain rollup. This month, developers at Rollkit used Ordinals to introduce Bitcoin’s first sovereign rollup.
For the first time ever, Ordinals enable anyone to publish large amounts of data (approximately 3.9MB) to Bitcoin’s blockchain. Unlike any other blockchain or cloud storage provider — which might go offline, fork, change developer specs, experience hacks, or migrate data centers — Bitcoin’s blockchain is a unique, permanent, immutable storage solution.
Permanence for each and every byte is critical for cryptographic hash functions which break consensus if even one period, space, or character is out of place. SHA-256 hashes only verify exact, character-by-character data. For this reason, users of other blockchains — including Ethereum — are suddenly taking interest in publishing Ordinals data to Bitcoin’s blockchain. With its multi-billion dollar security budget and surviving over a decade of relentless attacks, Bitcoin’s blockchain is the Internet’s most permanent storage solution.
Rollkit introduces a novel layer 2 using a Bitcoin sovereign rollup
Thanks to Ordinals’ ability to inscribe over 3.9MB of arbitrary data directly onto Bitcoin’s blockchain, Rollkit has created a Layer 2 called the Bitcoin sovereign rollup.
- A rollup is a batch of transactions or data that is “rolled up” in an orderly way for periodic, mainnet submission. Rollups are often popular for expensive mainnets like Ethereum’s blockchain. Cost-savings are significant when compiling a bunch of transactions and data, using cryptography to transform them into one single data, and then submitting this rollup to mainnet.
- Rollup technologies process data off-blockchain. This is why a rollup is a layer 2, or an “off-chain scaling solution.” It’s not a layer 1 blockchain but rather a second layer altogether.
- Sovereign, as the term implies, indicates that the rollup data is self-sufficient. Specifically, blockchain developers refer to rollup sovereignty as a data availability guarantee of 100%. In other words, a rollup is only sovereign if it can guarantee that the full, unabridged, and unhashed data it has rolled up will always be available for verification.
Rollkit’s new sovereign rollup uses Bitcoin’s blockchain as a data availability layer. The sovereign rollup’s framework toolkit borrows some capabilities from Casey Rodarmor’s Ordinals project which inscribes large amounts of arbitrary data into Bitcoin blocks.
Running the Ethereum Virtual Machine on Bitcoin
Rollkit launched a Bitcoin sovereign rollup as its second data availability and consensus option. Initially, Rollkit only supported Celestia sovereign rollups — Celestia is a modular, non-validating blockchain popular with Ethereum and Cosmos users.
Rollkit, formerly known as Rollmit, describes its toolkits as modular integration units. A Bitcoin sovereign rollup toolkit may, for example, provide settlement and execution functions on a separate blockchain altogether.
To state this explicitly, Rollkit’s Bitcoin sovereign rollup makes it possible to run entire software programs using on-chain Bitcoin data. Already, people are playing video games using 100% Bitcoin data. Now, someone may run the Ethereum Virtual Machine on Bitcoin.
More exotic possibilties
Like Ordinals, the new Rollkit integration uses Taproot and the Segwit witness discount to write over 3.9MB of arbitrary data into any Bitcoin block. It created two new functions for sovereign rollups that can send data to the data availability blockchain (Bitcoin) and retrieve data from earlier Bitcoin blocks. It can roll-up data into a single transaction to be sent to the Bitcoin blockchain, like most rollups such as Arbitrum and Optimism do for Ethereum. This feature can keep transaction costs under control.
As Protos previously covered, Ordinals have risen in popularity as a way to inscribe additional data onto individual satoshis. The idea of using bitcoin to store data other than financial transactions has long been a controversial one. Even Satoshi Nakamoto led an early attempt at a blockchain-based DNS-like system called Namecoin which used data on Bitcoin’s blockchain for non-financial purposes.
Rollkit says it can solve some of the issues with using Bitcoin to store “extra” data like NFT images, audio, video, and software files. Rollkit claims its sovereign rollups can handle execution and settlement.
However, some observers expressed skepticism.
- Ledger firmware engineer Salvatore Ingala doubted that Rollkit’s new tool would catch on.
- Others were less than excited about Rollkit describing basic “read” and “write” functions. They noted the need for centralized oracles to attest to usable data across blockchains.
- Ryan Berckman described the idea of sovereign rollups as an “alternative layer 1” that sends its data to Bitcoin.
In summary, the Ordinals project on Bitcoin is about much more than NFTs. Another unintended capability of publishing over 3.9MB of arbitrary data into a single Bitcoin block has allowed Rollkit to introduce a novel layer 2 called Bitcoin sovereign rollups. It could, for example, allow someone to run an EVM using only Bitcoin data. The discovery is only days old, and developers are actively experimenting with even more exotic use cases.